Figure 1. Brain and blood HMGB1 measurements during epileptogenesis evoked by electrical SE in adult rats.

(A) Representative photomicrographs of hippocampi from control rats (sham) or rats at 3 hours, 6 hours, and 4 days after SE (n = 5 each group). Top row shows HMGB1 immunoreactivity in cell nuclei (arrows) or in cytoplasm of glial cells (arrowheads). Immunofluorescence panels show localization of HMGB1 signal (green) in OX-42–positive microglia (red), GFAP-positive astrocytes (red), and EBA-positive endothelial cells (red); colocalization signal is depicted in yellow (merge). White arrows depict cytoplasmic staining. Hoechst-positive nuclei are shown in blue. Rad, stratum radiatum; LMol, stratum lacunosum moleculare. Scale bars: 25 μm (top row); 20 μm (bottom row; immunofluorescence panels). (B) Levels of HMGB1 isoforms in brain tissue (hippocampus) and corresponding blood of rats during epileptogenesis. Data are shown as mean ± SEM (n = 5 each group). Dot plots are shown in Supplemental Figure 4. *P < 0.05; **P < 0.01, Kruskal-Wallis test (referred to both isoforms in each bar). Blood acetylated and disulfide HMGB1 levels at 4 days are significantly different from corresponding 3-hour and 6-hour levels (P < 0.01).